In the art, a grill is typically placed in the front of a vehicle to guide air to its radiator. In additional to its ventilation function, the grill can also provide protection to the radiator and give the vehicle a distinctive appearance. It can be desirable to vary air flow to the radiator and vehicle front end aerodynamics based on various factors, such as driving conditions and engine temperature. For example, under high speed driving conditions, a closed front end grill can reduce vehicle air resistance and thus improve vehicle fuel efficiency. Also, optimal warm-up and temperature control of an internal combustion engine can improve fuel efficiency, improve engine performance, reduce emissions, and prolong engine life. Varying front end grill engine ventilation can be a useful tool to assist in achieving optimal engine temperature in many situations, such as during engine warm-up, cold ambient temperatures, and the like.
Variable ventilation of a front end grill is known in the art. For example, U.S. Pat. No. 4,457,558 to Ishikawa describes a system having a louvered grill associated with an air spoiler that are controlled based on vehicle speed and engine temperature. As vehicle speed increases, the air spoiler is opened to provide ventilation to the engine. A thermostat controls the amount of the grill ventilation through the louvers, having as its natural state a closed position to reduce wind resistance. While this system is effective, it is fairly complicated, uses a fair amount of parts, and appears geared more toward high vehicle performance. Also related to wind resistance as a function of grill ventilation is DE3916907 to Volkswagen AG. This invention has a variable wind resistance that increases to maximum wind resistance during heavy braking to provide high wheel force to the front wheels during the braking.
Other art, such as US 2008/0073920 to Knauer, discloses a grill with at least one flow-through opening and an assembly movably positioned behind the grill and matched to the geometry of the flow-through openings of the grill. In situations where closure of the flow through opening(s) is desired, the entire assembly is moved forward to block air flow. While this provides a simple design, it is unclear how the strip elements are actuated towards the grill. In any event, the assembly would most likely require a significant amount of room between the grill and the radiator.
Louvered variable grills are also known in the art. For example, U.S. Pat. No. 5,732,666 to Lee describes a plurality of louvers (directional control fins) actuated by temperature control sensors. A motor with a worm gear drives a pinion connected to one of the louvers. This movement is translated to the remaining louvers via a link bar.
While this technology marks a great advance in the art, further advances are possible. For example, the drive motor only drives one louver and is mounted at right angles to the louvers. This creates a bulky arrangement, since the motor extends rearward toward the radiator. The present invention attempts to overcome these shortcomings in the art by providing a grill ventilation system that allows vertical placement of the motor while directly driving each of the louvers.